Electrolytic rectifier



May 17 1927.

- L. J. KEELER ELECTROLYTIC RECTIFIER Filed Jan. 18. 1926 E m W F u m R u B MAGNESIUM .ELELLIRDD E ELEEIBIIU E g .1, KEELER Sid till

Patented May 1 7, 1 9 27.

UNITEDSTATES PATENT OFFICE.

LEWIS JAMES KEELER, OF CLEVELAND, OHIO, ASSIGNOR, BY DIRECT MESNE AS- SIGNMENTS, OF. ONE-HALF TO LE TRUE 1. BENSING, OF CLEVELAND,.OHIO, AND ONE-HALF T0 GEORGE I. KOELLIKER, 0F CLEVELAND HEIGHTfi, ()HIO.

ELECTROLYTIC RECTIFIER.

Application filed Jemm ie, rose. Serial rm. clear.

This invention relates to electrolytic rectifiers, that is, to devices for converting an alternating current into a direct current,and the invention is an improvement in the electrolytic rectifiers disclosed in the co-pending applications oi Le Rue P. Bensing. iderial Nos. 28,524:, and 53,750, and which rectifiers comprise certain metals and electrolytes adapted to prevent the positive phase of the alternating current from flowing but allows the negative phase to flow freely. My present object is to use the same metals set forth in said applications or any other metal having the inherent property to function as an electrolytic valve, and as a non film electrode, with a modified electrolyte, whereby I obtain a very permanent rectifier which can he used for charging storage batteries, as a condenser, and especially as an A and B hattery eliminator, for radio apparatus.

in the accompanying drawing, the single figure is a sectional View of a rectifier constructed according to my invention.

As shown, the rectifier comprises a suitahle jar or container 2 "for aqueous electrolyte 3, in which two metal electrodes 4e and 5 are suspended, preferably from a cap or cover 6, it being understood that this showing merely exemplifies a common arrangement of vparts in which the invention may be present. Thus, the container or jar 2 may be of glass or other material, and cap 6 may he made oi hard ruhher having openings through which the electrodes may extend into the jar about two inches apart and down to within a few inches of the loottom of the jar. ()ne elec trode 4, may he made of or contain'niagnesiuuuand the other-electrode 5 maycom sist or nickel, a nickel alloy, or any other suitable metal, The magnesium electrode may be protected from the atmosphere and from the galvanic action of the electrical connection by using a terminal 7 of any de sired protecting material which may be at fixed to the electrode in any suitable manner. I a I am aware that an electrolytic valve actron is a characteristic of magnesium, and in my experiments I find that magnesium or a magnesium base alloy will show valve action in a great number of solutions. But in nearly all of them there is no permanency.

In the electrolyte which I employ together with a magnesium electrode and a nickel soluble.

cent compound will rectify perfectly with magnesium or its alloys usedas an electrode.

In some compounds used as the aqueous elec.

trolyte, there will he an attack on an electrode oi magnesium, due to the fact that at certain voltagesthere will he a hrealring down of the film,.thusallowing some ofthe positive phase to flow; "which disintegrates the magnesium. in other solutions an elec trode of nickel or other metal will he tacked, and still others give harmful fumes h in my electrolyte, ll allralescent compounds, from one percent to any concentration obtainable, :tor example, compounds of organic acids, such as Rochelle salt," phosphates like ori-sodium phosphate; oleates;

and the alkali metal hydroxides, which are alcove classifications will serve as an electro lyte When used with a fluoride and mag;- nesiurn or its alloys, hut l have discovered that a berated fluoride gives the loest results.

ln that connection hydrofluoric acid of any percentage has no dissolving e'hfect on magnesium it the magnesium is allowed to remain in a solution of hydrofluoric acid, Whether the solution is cold or hoiling. New, ii magnesium or magnesium hase alloy he made the rectifying element in such a solu- Again an alkali metal hydroxide is,

talren'it will ice-found that magnesium or its alloys is not afiected by any concentration of an alkali hydroxide solution, whether it may be cold or boiling. It the alkali metal hydroxide, say potassium hydroxide be made As before mentioned any the horates; cyanides such as sodium cyanideszg.

too.

the electrolyte, it will be noticed that magnesium will rectify the alternating current to direct current. The condition must be quite exact though. The film formed on the magnesium will not withstand a suitable voltage thus allowing a positive current to flow which has a tenfold bad effect, that of poorly filtered current and a wearing away of the magnesium rectifying element. Also the solution gives off bothersome fumes.

If a simple fluoride salt is used such as potassium fluoride rectification is without fault, and a number of metals are unaltered by such an aqueous solution if neutralized or made slightly alkaline. When an aqueous solution of potassium fluoride is used as the electrolyte and magnesium or magne-' sulphuric acid electrolyte and the cathode anode have great permanency. fhe electrolyte has suitable conductance and there are no odors given oil when the cell is in operation.

The concentration of the electrolyte may vary within wide limits, say from one percent of an alkalescent compound to its saturation point, and one percent of a water soluble fluoride to its saturation point, dependent upon the commercial application. The solubility may be increased in cases where the solubility is low, say boran which may be increased greatly by adding a large amount of glycerine, or by the very presence of fluoride the solubility of borai: is in= creased. Borax is soluble to three to four parts per hundred in water at about twentylive degrees centigrade, whereas in a fluoride the solubility of borax is increased ten percent or more according to the concentration of the fluoride.

As an example, l will now describe a suitable combination in detail as l prepare it and use it in my rectifier.

l take 800 grams of chemically pure potassium fluoride and dissolve it in 500 cubic centimeters of distilled water. if the solution is not acid, it is made so, with hydrofluoric acid and boiled for five minutes.

This operation can be performed in a pyrex beaker; then 100 grams of borax are added and the solution heated until all of the salt is in solution. The solution is filtered, and

u; reasgrsa when cooled made up to 1000 c. 0.; this will give a solution or electrolyte containing 30 percent of potassium fluoride and percent of borax. This solution or electrolyte provides an ideal permanent rectifier; the conductivity is very good; and the rectifier may be operated successfully Without attention except for the addition of Water at intervals. I do not wish to confine myself to the exact percentages in the solution given as I may use any percentage of salts from a very small percent to as much .as can be dissolved in an aqueous solution, since magnesium'is not attacked at any concentration by the above aqueous solution.

What I claim, is:

1. ll. permanent electrolytic rectifier, comprising an anode, a cathode, and a. borated fluoride electrolyte in which the fluoride is in a preponderating amount relatively to the borate.

2. A permanent electrolytic rectifier, in-

cluding an electrode containing magnesium,

and a fluoride electrolyte containing a substance having borate properties, the fluoride being in excess of the borate.

3. A permanent electrolytic rectifier, comprising a rectifying element, an electrode containing nickel, and a borated fluoride electrolyte in which the fluoride IIIBXCQSS of the borate. 1

i. A permanent electrolytic rectifier, com; prising an electrode containing magnesium, an electrode containing nickel, and a borated tluoride electrolyte, the fluoride in the electrolyte being in preponderance to the borate.

5. A permanent electrolytic rectifier, comprising an anode, a cathode, and an aqueous electrolyte containing a borated fluoride, the fluoride being in excessof one percent and in excess of the borate.

6. A permanent electrolytic rectifier, comprising an anode, a cathode, and an aqueous electrolyte containing approximately thirty percent of potassium fluoride and ten percent of boran.

7. A. permanent electrolytic rectifier, comprising an anode, a cathode, and a potassium fluoride electrolyte containing boraa,

the lino-ride being approximately two to three times in excess of the borate used.

8. An electrolyte for electrolytic rectifiers, comprising a fluoride and a borate, cride being in excess of the borate.

9. An ,electrolyte for electrolytic rectitiers, com rising a fluoride, a lesser percent age of a rate, together with glycerme to enhance the solubility of the borate.

l0 An electrolyte for electrolytic rectifiers, comprisin a fluoride and borax, the amount of fluoride in solution being at least double the amount of borax.

ln testimon whereof I affix my si nature.

EWIS JAMES Kantian.

the flu- I 

